I haven't been really good at doing the exercises on a daily basis, but the first 11 or so are just "warm up" exercises, to get the muscles involved stretched and ready...the next few are sounds, and iirc there's an alphabet exercise.
I do remember thinking (after about a week) that I could feel my throat/voice area getting more used to being in the higher ranges (I do use a pitch meter, btw...I have two of them, one is mentioned in FYFV, and the other can be found by googling "Overtone Analyzer Free Edition"). The more used to doing it, the easier it got (and that was with just a couple weeks' use, before I got distracted with other things. Oooh! OOooh! Shiny!! ...LOL

)
Consistent, daily practice should yield good results. And of course, not just practicing, but using the techniques in your daily life as opportunities come up.